1. Technical Field of the Invention
The present invention relates to a ROM writer that updates a control program stored in a built-in ROM of a card PC and a ROM program updating method. More particularly, the invention relates to a ROM writer and a ROM program updating method that can readily update a control program.
2. Conventional Technology
In recent years, PC boards equipped with a CPU, ROM and the like that realize various functions of a computer have been developed. There are demands for PC boards with greater speeds, higher-level functionalities, and smaller sizes, and so-called card PCs in which a CPU, ROM and the like are concentrated and disposed therein have been developed.
A card PC is equipped with a built-in ROM that stores a system control program (BIOS) that realizes predetermined functions of the system.
The ROM that stores the control program can be removed by means of a socket or the like. In this case, when a ROM is updated, only the ROM is removed, a program is written thereon by an independent gang writer, and the ROM is mounted again.
Alternatively, when the ROM is updated without being removed, the OS is started by a control program stored in a built-in ROM, and a ROM update program is operated to update the built-in ROM.
Moreover, a function for updating a built-in ROM may be provided within the built-in ROM.
The use of a socket poses a restriction on the mounting space, and causes poor manageability in terms of maintenance since the system substrate needs to be accessed when the ROM is updated.
Also, when a built-in ROM is to be updated after the OS is started and the ROM update program is operated, or when a built-in ROM is to be equipped with a function to update the built-in ROM, the built-in ROM and the update program within the built-in ROM need to be maintained in perfect condition. For this reason, if data in the built-in ROM is damaged, the OS and the update program may not operate normally.
There is another instance where an overwrite of the update program section may be masked by a boot block scheme. However, the destruction of the program cannot be avoided when an unexpected voltage is applied by an accident or the like. Also, when a boot block is written in for masking, the boot block cannot be updated from the system.
Furthermore, when an built-in ROM is mounted on a so-called card PC, it needs to be entirely disassembled and then reassembled when the ROM is updated, which leads to poor manageability in terms of maintenance.
The present invention has been made in view of the problems described above, and one object of the invention is to provide a ROM writer and a ROM program update method in which a control program that is stored in a built-in ROM of a card PC or the like can be readily updated.